Synergistic effect of net-houses and light sources on the enhancement of off-season flowering waves and production of ‘Da Hong’ red-fleshed pitaya

Abstract

To meet the increasing demand for year-round production of ‘Da Hong’ red-fleshed pitaya (Hylocereus polyrhizus), which is limited by its natural flowering season in the summer and has been a dominant cultivar in Taiwan, China and East-SouthEast Asia owing to its self-compatibility and excellent fruit quality, extending the off-season cultivation period has become a crucial endeavor. This study aimed to assess the effects of net-houses and light sources on off-season (spring and winter) fruit quality yield of ‘Da Hong’ red-fleshed pitaya in Taiwan. Mature six-year-old plants were cultivated either in net-houses or open fields (OFs), with night-breaking achieved using artificial lighting: either 100 W incandescent bulbs (IBs) or 23 W compact fluorescent energy-saving bulbs (CFBs). The study was conducted during spring and winter in 2017–2018, with flowering rate and fruit production evaluated. Floral bud emergence in the net-house+IB and net-house+CFB groups preceded that in other treatments by at least 2 weeks during spring, with net-house+IB exhibiting the highest frequency of flowering waves (four in spring and three in winter). Across all treatments, night-breaking via artificial lighting in spring markedly increased yield, with IBs and CFBs producing similar outcomes. Quality-wise, OF cultivation surpassed net-house cultivation in spring, whereas net-house cultivation, particularly with IBs, proved more effective during winter. In summary, net-house cultivation offers several advantages for off-season production, including earlier peak flowering in spring, increased flowering cycles in both spring and winter, and higher flowering rates during winter. Overall, these results may help enhance and stabilize off-season ‘Da Hong’ red-fleshed pitaya cultivation. Moreover, the significance of our study has the potential to revolutionize the flowering physiology, the strategy to enhance year-round production and the advancement of agricultural sustainability in pitaya.